package util;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Map;
import java.util.logging.Logger;

public class SimpleBeanConvertor {
    private static Logger logger = Logger.getLogger(String.valueOf(SimpleBeanConvertor.class));
    /**
     * 将HTTP请求中的参数赋值给指定类型JavaBean的相关属性
     */
    private static Object parseValue(String[] value,Class type) throws ParseException, UnsupportedTypeException {
        if (String.class == type)
            return value[0];
        if (java.util.Date.class==type)
            return new SimpleDateFormat("yyyy-MM-dd").parse(value[0]);
        if (boolean.class ==type || Boolean.class == type)
            return true;
        if (char.class ==type || Character.class ==type)
            return value[0].charAt(0);
        if (int.class ==type || Integer.class ==type)
            return Integer.valueOf(value[0]);
        if (short.class ==type || byte.class ==type || long.class ==type || float.class ==type ||double.class==type)
            try {
                type =Class.forName("java.lang."+type.getName().substring(0,1).toUpperCase()+type.getName().substring(1));
            }catch (ClassNotFoundException e){
                e.printStackTrace();
            }
        if (type.getName().startsWith("java.lang.")||type.getName().startsWith("java.math"))
            try {
                return type.getConstructor(String.class).newInstance(value[0]);
            }catch (Exception e){
                throw new UnsupportedTypeException(e);
            }
            throw new UnsupportedTypeException();
    }
    public static <T> T convert(HttpServletRequest request,Class<T> targetType) throws InstantiationException, IllegalAccessException, InvocationTargetException, ParseException, UnsupportedTypeException {
        Map<String, String[]> params = request.getParameterMap();
        if (params.size()==0)return null;
        T target = targetType.newInstance();
        Method[] allMethods = targetType.getDeclaredMethods();
        if (allMethods != null && allMethods.length>0){
            for (Method method : allMethods){
                if (method.getName().startsWith("set")){
                    Class[]args = method.getParameterTypes();
                    if (args.length ==1){
                        String paraName = method.getName().substring(3,4).toLowerCase()+method.getName().substring(4);
                        if (params.containsKey(paraName)){
                            try{
                                Object value = parseValue(params.get(paraName),args[0]);
                            }catch (Exception e){
                                logger.info("参数转换错误");
                                e.printStackTrace();
                                throw  e;
                            }
                        }else if (Boolean.class == args[0] || boolean.class==args[0]){
                            method.invoke(target,false);
                        }
                    }
                }
            }
        }
        return target;
    }
}
